You can read through the threads on them...essentially, they are old worn out tire carcasses that have a new rubber cap glued onto them in the shape of a new tread...typically imitating the tread pattern shapes of past generation popular mud tires once the OEM manufacturer goes to an improved pattern, etc. (Helps avoid patent issues...)
They use AT tires as the carcasses, even though they sell them as MT's...so they LOOK like MT's, but the sidewalls, etc, are from AT's. If its using the BFG AT ko carcass, at least the sidewalls are not too bad, but the 2-ply AT ones they also use are much more vulnerable to rock damage, unlike what the nice looking 1st gen MT/R imitation tread patterns might imply.
If you use it in mud and not sharper terrain, an AT carcass if not dry rotted, etc, is typically OK though. The DOT states a tire older than 6 years from its sidewall manufacturer date should be taken out of service though...due to rotting of the sidewalls due to ozone, UV light, etc. The original sidewall date for the retread's donor carcass is still your limiting factor. Personally, for the BFG AT ko at least...I think 6 years is too conservative, and I think they are more resistant to rot than many others, but perhaps at ~ 8-10 years you're still really pushing it. (Worth looking at the donor carcasses DOT Date to avoid too old a carcass)
While a new tire can fail too, it is not common for a new tire to have its tread fall off. It is not common for a treadwright tread to come off either, but, they do delaminate from time to time, and more often than for a new tire by a good margin. (On a new tire, the tread is part of the tire
...so it doesn't "fall off" really...)
Happiness depends on how lucky you are.
We see time and time again that its a lot like smoking: MOST people who smoke don't get cancer...but, statistically, more people who smoke do get cancer.
So, if you are one of the lucky ones who doesn't get cancer, you get to say " Smoking is fine, I've been smoking for XXX years and it never hurt ME"
If you are one of the unlucky ones...you get to say "I smoked for XXX years and then got lung cancer".
Same for retreads...the people who DIDN'T have a problem say " I've been using retreads for XXX miles/years and never had a problem"...
..and the people who DID have a problem are really angry and feel duped.
People who get retreads coincidentally are statistically more likely to also smoke...as it's inline with their worldview (More likely doesn't mean 100% etc...)
So, the question is always "Do you feel lucky?"